Microsoft Corporation has developed specifications and software for an automotive entertainment and computer accessory system that includes a variety of different elements such as a security subsystem, a navigation subsystem, and an entertainment subsystem. These elements are implemented in part by computer programs that execute under the control and supervision of an operating system.
The operating system implements a graphical user interface (GUI) similar to popular desktop operating systems. Such operating systems typically have application programming interfaces (APIs) for use by application programs. Application programs can use the APIs to easily create different types of operator interface controls. For example, the operating system might make available a "list box" control. A list box is used to display a list of choices, such as text, color, icons, or other graphics, from which the user can select one or more items. A variety of other controls are also available as described in Simon, Richard, Windows 95 Win32 Programming API Bible, Book 1, Waite Group Press, 1996. This reference is hereby incorporated by reference.
Although such controls have been very effective in the desktop environment, they are difficult to work with in an automotive accessory having a relatively small display size. The invention embodiment described below has a color graphics panel with a resolution of only 256.times.64 pixels. No more than about four lines of text can be legibly displayed on such a panel. This factor makes it very difficult to work with traditional controls such as list boxes, drop-dowm list boxes, combo boxes, etc.
In addition, there are other factors that must be considered when designing an effective operator interface in the automotive environment. For example, the lighting in an automobile often results in high display contrast and glare, accompanied by generally low light levels that make it difficult to discern small graphical elements, especially on LCD displays. Furthermore, the user of the operator interface is often the driver of the automobile, who should be able to perceive presented information with little more than a quick glance.
With these factors in mind, the inventors have sought to design an interface and associated controls that are more effective in the automobile environment than traditional interfaces and controls.